Spotify won't ever make a profit because of one-sided deals with record companies that give Spotify the short end of the stick every time, according to MP3.com founder Michael Robertson.

Spotify isn't the only service at risk — all the other online radio and music streaming services like MOG and Rdio also face similar problems with record companies, he wrote in a blog post on GigaOm. Here's what Robertson, a 15-year veteran in the digital music industry, had to say:

The supplier will always elect the formula that captures the largest amount of money for themselves, completely disregarding the financial viability of the store. If the store miraculously managed to generate a profit, the landlord would simply raise the rates after two years... These details aren’t well-known because digital music service deals are always wrapped tightly with strict non-disclosure agreements.

With most other businesses, if a supplier makes unreasonable demands, a retailer can turn to other providers. Since copyright law gives record labels and publishers a government-granted monopoly, no such option is possible with music. Digital vendors have only two options: Accept the terms or not include those songs in their offering.

Here are some of the constraints record labels place on companies like Spotify:

Record companies charge per play or per subscriber, or take a percentage of the total revenue of the company, regardless of additional revenue streams outside of plays.

Record labels also typically receive equity stake in music streaming companies.

Labels ask for large up-front or minimum payments to access the music.

Music-streaming services have to deliver incredibly detailed reports that are very time- and resource-intensive to build.

Companies like Spotify have to convert any music file into a unified file format, and record companies rarely deliver them in the same format.

Music-streaming companies also have to sign deals with publishers, not just record labels.

Each record label asks that its deal be as good, or better, than deals with other record labels regardless of library.

Music-streaming companies aren't allowed to disclose how much they pay out to record labels.